When the U.S. Federal Reserve assesses the rate of inflation in the nation, it prefers to use something called the personal consumption expenditures price index.

The PCE, which is published by the U.S. Commerce Department’s Bureau of Economic Analysis, tracks changes in real prices paid by consumers for goods and services and captures how those changing prices influence consumer behavior.

See how it works and compares with another common inflation gauge, the consumer-price index. Read More »

Every March 14 for the past 27 years, a lot of otherwise rational folks celebrate the irrational: pi.

Pi Day–celebrated on 3/14, or the month/date format that coincides with the numerals 3.14 that begin pi–is the celebration of the irrational number that represents the ratio of a circle’s circumference to its diameter. In other words, if you know or can determine either the circumference or the diameter of a circle, you can use pi to calculate the unknown.

A number of people have tried to calculate their chances of finding love by using the Drake Equation, a probability formula devised to estimate the number of planets that could sustain intelligent life.

But Andrew Gelman, a professor of statistics and political science at Columbia University, says that’s the wrong approach.

“The chance of it happening on any one day is about 1 in 3,650,” he said (not accounting for Leap Days over a presumed 10-year span). “If there is only a 50% chance of it happening, the odds are roughly 1 in 7,000.” Read More »

While zero is not a pure counting number, today’s offering provides an inviting window through which to look back at some recent fiscal thinking: Around the turn of the century, U.S. budget forecasters (from both sides of the aisle) predicted the national debt would one day be zero. As in nil, nothing.

About The Numbers

The Wall Street Journal examines numbers in the news, business and politics. Some numbers are flat-out wrong or biased, while others are valid and help us make informed decisions. We tell the stories behind the stats in occasional updates on this blog.